# US 8,785,890 B2 · Charged particle beam apparatus permitting high-resolution and high-contrast observation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,785,890 B2 - Document ID: US8785890B2 - Status: Granted - Kind: B2 - Application number: 13/871,624 - Filed: 2013-04-26 - Published: 2013-09-05 - Granted: 2014-07-22 - Earliest claimed: 2008-04-14 - Assignees: Hitachi High-Technologies Corporation - Applicants: Hitachi High-Technologies Corporation - Inventors: Muneyuki Fukuda; Naomasa Suzuki; Tomoyasu Shojo; Noritsugu Takahashi - Web page: https://patentgrep.com/patent/US8785890B2 ## CPC - H01J 37/28: with scanning beams {(H01J37/268, H01J37/292, H01J37/2955 take precedence)} - G01N 23/225: using electron or ion - H01J 37/145: Combinations of electrostatic and magnetic lenses - H01J 2237/21: Focus adjustment - H01J 2237/28: Scanning microscopes - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract A lower pole piece of an electromagnetic superposition type objective lens is divided into an upper magnetic path and a lower magnetic path. A voltage nearly equal to a retarding voltage is applied to the lower magnetic path. An objective lens capable of acquiring an image with a higher resolution and a higher contrast than a conventional image is provided. An electromagnetic superposition type objective lens includes a magnetic path that encloses a coil, a cylindrical or conical booster magnetic path that surrounds an electron beam, a control magnetic path that is interposed between the coil and sample, an accelerating electric field control unit that accelerates the electron beam using a booster power supply, a decelerating electric field control unit that decelerates the electron beam using a stage power supply, and a suppression unit that suppresses electric discharge of the sample using a control magnetic path power supply. ## Claims ### Claim 1 A charged particle beam apparatus, comprising: a stage for placing a sample thereon; a detector detecting secondary charged particles generated due to irradiate a primary charged particle beam to the sample; an objective lens that focuses the primary charged particle beam on the sample and having an opening through which the primary charged particle beam passes; and a power supply unit applying a negative voltage to the sample, wherein the objective lens includes: a first magnetic pole member that is disposed around the opening and has a terminal portion at a sample side thereof that functions as an upper magnetic pole member of the objective lens; a second magnetic pole member that supplies a magnetic flux to the first magnetic pole member and is formed with a hollow interior; a coil that is disposed within the second magnetic pole member and supplies a magnetic flux to the second magnetic pole member; and a third magnetic pole member that is disposed between the stage and the second magnetic pole member, has the opening and functions as lower magnetic pole member of the objective lens, and wherein a potential lower than that of the second magnetic pole member is supplied to the third magnetic pole member. ### Claim 2 (depends on 1) The charged particle beam apparatus according to claim 1, further comprising: means for supplying a retarding potential to the sample, wherein a potential higher than the retarding potential is supplied to the third magnetic pole member. ### Claim 3 (depends on 2) The charged particle beam apparatus according to claim 2, wherein a potential difference between a potential at the sample and a potential at the third magnetic pole member is within 100V. ### Claim 4 (depends on 3) The charged particle beam apparatus according to claim 3, wherein the potential at the third magnetic pole member is equal to the potential at the sample. ### Claim 5 (depends on 2) The charged particle beam apparatus according to claim 2, wherein an accelerating potential for accelerating the primary charged particle beam is applied to the first magnetic pole member. ### Claim 6 (depends on 1) The charged particle beam apparatus according to claim 1, further comprising: means for electrically isolating the second magnetic pole member and the third magnetic pole member from oath other. ### Claim 7 (depends on 1) The charged particle beam apparatus according to claim 1, wherein the second magnetic pole member is brought to a ground potential. ### Claim 8 (depends on 1) The charged particle beam apparatus according to claim 1, wherein a bottom of the second magnetic pole member has a conical shape with the opening, and wherein the third magnetic pole member is realized with a magnetic plate disposed in parallel with a conical surface of the conically-shaped bottom with a predetermined gap left from the conical surface. ### Claim 9 (depends on 1) The charged particle beam apparatus according to claim 1, further comprising: an electrostatic adsorption device that holds the sample. ### Claim 10 (depends on 9) The charged particle beam apparatus according to claim 9, wherein the electrostatic adsorption device includes: an internal electrode that is opposed to the sample with a dielectric between them; a contact electrode that applied a retarding voltage to the sample; and means for retaining a potential difference between a potential at the contact electrode and a potential at the third magnetic pole member at a value falling within −±100V. ### Claim 11 (depends on 1) The charged particle beam apparatus according to claim 1, further comprising: a cooling member for the third magnetic pole member. ### Claim 12 (depends on 1) The charged particle beam apparatus according to claim 1, further comprising: means for acquiring a shaded image of a portion of irradiation of the primary charged particle beam. ### Claim 13 (depends on 1) The charged particle beam apparatus according to claim 1, wherein the third magnetic pole member has two magnetic plates of an upper magnetic plate and a lower magnetic plate; and wherein the lower magnetic plate is brought to a same potential as a potential at the sample.